Recently, as a robot technology is developed, a use of a mobile robot setting its own path and moving along the set path has been increased. An a representative of the mobile robot may include a cleaning robot cleaning the inside of a house or a building, a guide robot guiding location, and the like. In particular, the cleaning robot cleans an indoor floor using a vacuum cleaning unit provided therein while moving including various sensors and heading units. Currently, various types of cleaning robots have been commercialized.
There is a need to build a map for a space in which mobile robots move and allow the mobile robots to recognize their own locations in the space in order for these mobile robots to effectively determine their own locations in the space and move to the determined locations. Allowing the mobile robot to recognize its own location with respect to a surrounding space and build a map is referred to as simultaneous localization and mapping (SLAM).
Among the SLAM mechanisms, an image based SLAM builds a map for the surrounding environment using visual features extracted from an image and estimates a posture of robot. Generally, the mobile robot is headed based on dead reckoning by using a gyroscope and an encoder provided in a driving motor and analyzes an image using a camera mounted at a top thereof and build a map. In this case, when an error occurs due to odometry from the gyroscope and the encoder, an accumulated error is corrected by using image information acquired from the camera.
Several related arts for a method for controlling heading of a mobile robot and a mobile robot using the method have been proposed, but do not solve the following problems.
As descriptors for features extracted from an image, several types have been used. However, there is a problem in that these types do not show robust performance when illumination is greatly changed or an image is greatly changed. Further, adaptive heading control mechanisms that can cope with environments in which an input image cannot be used or a heading control error of the mobile robot occur in controlling the heading of the mobile robot have not yet proposed. Further, even though the features are different from each other, a problem of falsely recognizing the different features as the same feature in feature matching has frequently occurred.